In recent years, mechanical assist devices have been developed for assisting the heart, especially a weak or impaired heart, in the blood pumping function. One such mechanical assist device is the intra-aortic balloon. A technique for introducing the intra-aortic balloon into the body has been developed, which technique enables the intra-aortic balloon to be inserted percutaneously. In using the percutaneous technique, the intra-aortic balloon is twisted or wrapped to significantly reduce its outer diameter prior to insertion. The intra-aortic balloon is then inserted into a percutaneous sheath which extends at least partially into an artery such as, for example, the femoral artery.
The sheath presently employed for percutaneous insertion has a relatively short length.
Arterial disease often makes it difficult to pass the intra-aortic balloon through the vascular system. The difficulty is especially pronounced when attempting to move the intra-aortic balloon past the bifurcation in the abdomen that branches the abdominal aorta into the right and left illiac arteries and, in turn, into the two femoral arteries. It is therefore extremely desirable to have a long percutaneous introducer sheath that is positioned well into the large abdominal aorta or even the thoracic aorta by means of a guide wire with a J-type tip. The long percutaneous sheath of the introducer allows the intra-aortic balloon to be placed past such obstructions and totally avoids subjecting the intra-aortic balloon to the lacerating insults of a build-up of arterial plaque.
The introducer sheath does, however, present some disadvantages. For example, once the intra-aortic balloon is properly placed, through the use of the percutaneous method, the long introducer sheath increases the overall size (i.e. outer diameter) of the effective balloon catheter with which it has been inserted in the artery and thereby obstructs the flow of blood within that artery to the leg, causing clotting and circulatory complications. To solve this problem, the introducer sheath is withdrawn from the body along the balloon catheter requiring that the balloon catheter itself be quite long, further necessitating that the balloon catheter be provided with a larger lumen for the extra length, to permit fast balloon actuation. The percutaneous introducer has the disadvantage of not being able to pass beyond the intra-aortic balloon to the extension hose coupling due to the large outer diameter of said coupling.
Another sheath removal technique which has been employed to alleviate this problem is to provide a peel-apart introducer sheath which is comprised of a sheath which is designed to peel apart due to only moderate stretching. In use, the sheath is inserted to the proper location within the body and thereafter the balloon is inserted, whereupon the sheath is withdrawn and either entirely or partially peeled away from the catheter. The peel-apart introducer sheath is similar to those employed in cardiac procedures when placing the pacing wires, utilized for example with pacemakers and the like. The peel-apart sheath is formed of a grain-oriented plastic material to facilitate splitting in an orderly manner.
The long sheath, which is typically of the order of sixteen inches in length, after being removed entirely, leaves only the small diameter balloon catheter within the femoral artery. Due to the small balloon catheter diameter, relative to the inner diameter of the femoral artery, excellent circulation is assured. However, removal of the sheath from the femoral artery, which necessarily has a larger diameter than the balloon catheter, may cause a potential bleeding problem when the smaller balloon catheter is the only remaining member penetrating the opening originally formed in the femoral artery to introduce the percutaneous sheath, balloon and balloon catheter.